This invention concerns a weighing system that uses a plurality of load cells.
Weighing systems of this type normally comprise a platform whereon a load to be weighed must be placed and a series of load transducers, the so-called load cells, located underneath the platform in a preset configuration.
When a load is placed on the platform, the load sensors are prompted, for example, by compression, by traction and by flexure and transmit a signal that is proportionate to the prompting to which they are subjected.
U.S. Pat. No. 4,804,052 describes a prior-art weighing apparatus comprising a plurality of load cells, a load receiver means supported by said load cells, a means associated with said load cells to supply a digital representation of the load lying on each load cell, a means for storing a mathematical expression for the loads that is corrected according to the position of the loads and a means for applying said mathematical expression to said digital representations of the loads to produce a digital representation of the total load on said load receiver means, said digital representation being corrected according to the position of the load.
In other words, for each load cell a correction coefficient of the indication supplied by the load cell is calculated, which is applied at each weighing operation to correct the indications of the different load cells in order to obtain a correct value of the load that is to be measured.
This system has the advantage that the weighing apparatus must always be connected to a dedicated data-processing system which, for each weighing operation, calculates the correct value of the load by applying the so-called correction coefficients to the indications provided by the different load cells. Furthermore, if the data-processing system has to be replaced for any reason the correction coefficients have to be recalculated, which results in loss of time and additional system running costs.